Protein-bound 4-Hydroxy-2-nonenal

Abstract

Several lines of evidence indicate that the nonenzymatic oxidative modification of proteins and the subsequent accumulation of the modified proteins have been found in cells during aging and oxidative stress and in various pathological states, including premature diseases, muscular dystrophy, rheumatoid arthritis, and atherosclerosis. Our previous work suggested the existence of molecular mimicry between antibodies raised against hydroxy-2-nonenal (HNE)-modified protein and anti-DNA autoantibodies, a serologic hallmark of systemic lupus erythematosus (SLE). In the present study, we investigated the possible involvement of HNE-modified proteins as the endogenous source of the anti-DNA antibodies. Accumulation of the antigen recognized by the antibody against the HNE-modified protein was observed in the nucleus of almost all of the epidermal cells from patients with autoimmune diseases, including SLE. The SLE patients also showed significantly higher serum levels of the anti-HNE titer than healthy individuals. To determine if a specific anti-DNA response could be initiated by the HNE-derived epitopes, we immunized BALB/c mice with the HNE-modified protein and observed a progressive increase in the anti-DNA response. Moreover, we generated the monoclonal antibodies, showing recognition specificity toward DNA, and found that they can bind to two structurally distinct antigens (i.e. the native DNA and protein-bound 4-oxo-2-nonenal). The findings in this study provide evidence to suspect an etiologic role for lipid peroxidation in autoimmune diseases.Several lines of evidence indicate that the nonenzymatic oxidative modification of proteins and the subsequent accumulation of the modified proteins have been found in cells during aging and oxidative stress and in various pathological states, including premature diseases, muscular dystrophy, rheumatoid arthritis, and atherosclerosis (1, 2). It has also been suggested that many of the effects of cellular dysfunction under oxidative stress are mediated by the products of nonenzymatic reactions, such as the peroxidative degradation of polyunsaturated fatty acids (3, 4). Lipid peroxidation leads to the formation of a broad array of different products with diverse and powerful biological activities. Among them are a variety of different aldehydes. The primary products of lipid peroxidation, lipid hydroperoxides, can undergo carbon-carbon bond cleavage via alkoxyl radicals in the presence of transition metals, giving rise to the formation of short chain, unesterified aldehydes of 3-9 carbons in length, and a second class of aldehydes still esterified to the parent lipid (5). These aldehydes generated during the lipid peroxidation have been implicated as causative agents in cytotoxic processes initiated by the exposure of biological systems to oxidizing agents.Some of the lipid peroxidation products exhibit a facile reactivity with proteins, generating a variety of intra-and intermolecular covalent adducts. Such adducts could be the targets of B cell-mediated immune responses a...

Identification of a Lipid Peroxidation Product as the Source of Oxidation-specific Epitopes Recognized by Anti-DNA Autoantibodies*

“…The involvement of lipid peroxidation was also suggested by the observation that lipid peroxidation-specific epitopes were detected in tissues from the SLE patients (13). These findings raised the possibility that the enhanced lipid peroxidation, through its pivotal role in oxidative stress, may be involved in the pathogenesis of autoimmune disorders.…”

“…However, the relatively long and hydrophobic sequence of the HCDR3, both ends of which are flexible residues (glycines and alanine), indicatesthat multiple conformational states and/or multiple dissimilar binding site conformations of HCDR3 enable the cross-reactivites of A1116 toward the ONE-modified proteins. It was also noted that both mAbs DSO and A1116 are encoded by VH genes that are similar to those found in the anti-DNA obtained from normal mice immunized with a protein-bound lipid peroxidation product (13). The similarity between the autoimmune and immunization-induced anti-DNA has been previously noted and supports the hypothesis that the development of the anti-DNA in normal and lupus-prone mice may occur by a common mechanism in which DNA or a protein-bound ligand stimulates B cells to differentiate in a receptor-mediated response.…”

“…In addition, we have examined the affinity of the anti-DNA mAbs D431 and D466 obtained from the 56R and CD40L-double transgenic mice (25,26), a spontaneous murine model of SLE, to the ONE-modified protein and found that, of the two anti-DNA mAbs, mAb D466 cross-reacted with the ONE-modified BSA. 3 Of interest, the anti-DNA mAb raised from the BALB/c mice immunized with the 4-hydroxy-2-nonenal-modified protein has been shown to crossreact with the ONE-modified protein (13). Several different antigenic cross-reactivities have been identified for the anti-DNA antibodies (27).…”

Differential oxidative modification of proteins in MRL+/+ and MRL/lpr mice: Increased formation of lipid peroxidation-derived aldehyde-protein adducts may contribute to accelerated onset of autoimmune response

“…Increased lipid peroxidation [4,18,19,22,24–26] and higher levels of MDA- and HNE-modified proteins have been reported in SLE patients [4,6,19,25,26,31,40]. However, significance of increased LPDA-modified proteins and their contributions to initiation and pathogenesis of SLE remain unclear.…”

Covalent Binding Antibodies Suppress Advanced glycation: On the Innate Tier of Adaptive Immunity

“…One hypothesis suggests that the carbonyl group serves as the reactive anchor for modification of self by the phospholipid moieties. Small aldehydes that are byproducts of lipid peroxidation, such as 4-hydroxynonenal and 4-hydroxyhexenal, are also implicated in protein damage and cytotoxicity and may play a role in autoimmune responses (41). Moreover, malondialdehyde, glycolaldehyde, and other reactive aldehydes generated from early glycation also contribute to LDL modification and to the production of autoantibodies in pathologic conditions (42).…”